King shags (Leucocarbo carunculatus) dispersing to feeding areas from breeding colonies on the Trio Islands and Stewart Island began to leave colonies around dawn, and most had left by mid-morning. Foraging birds were distributed throughout Admiralty Bay, the average distance from the colony was c. 10 km, and were observed only rarely where the water depth was >50 m. Greater areas of mussel farms in inshore waters could potentially affect king shags by restricting the area available for foraging.
The breeding biology of kakapo (Strigops habroptilus) was investigated on offshore island refuges between 1990 and 2002. Male kakapo typically attended their display territories between October to April, with the primary courtship display, “booming”, usually beginning in January and ending in March. Mating was recorded from late December to March, with the median mating date falling in late January. Eggs were laid from early January to late March, with median dates of 24 January on Little Barrier Island and 7 February on Codfish and Pearl Islands. Females typically occupied a nest site eight days after their last mating (n = 44) and laid their first egg two days later (n = 40). Subsequent eggs were laid at three day intervals (n = 41). The mean and modal clutch sizes were 2.53 and 3 respectively, (range = 1 – 4, n = 54). Mean mass of fresh eggs was 40.53g (n = 122). Incubation began immediately after the first egg had been laid and the average incubation period was 30 days (n = 28). Mean nestling and fledgling periods were 72.4 (n = 27) and 246 days (n = 25) respectively. Male chicks began to grow more rapidly than females approximately one third through the nestling period. The mean fledging weights of 14 male and 14 female chicks were 1.93 and 1.72 kg respectively. Male kakapo are capable of mating at five years of age. Three known-age females first nested at 9, 10 and 11 years of age, respectively. Comparison with close relatives suggests that some aspects of kakapo breeding biology are evolutionarily conservative.
The anticoagulant brodifacoum is widely used for the control and eradication of vertebrate pests in New Zealand. During poisoning operations with this toxin, some native birds eat baits and die. Because brodifacoum persists in the environment, other birds may suffer secondary poisoning from eating animals that have ingested the poison baits.We describe here high mortality of New Zealand dotterels (Charadrius obscurus) following an aerial brodifacoum operation at Tawharanui Regional Park, North Auckland, in 2004. At least 50% of the dotterels in the area at the time of the operation disappeared or were found dead; one bird found freshly dead had a high liver level of brodifacoum residue. Sandhoppers (Talorchestia spp.) are a common food item of New Zealand dotterels. Sandhoppers at Tawharanui ate baits and accumulated brodifacoum and provided a potential route for transmission of the toxin to dotterels. Three pied stilts (Himantopus himantopus) and one spur-winged plover (Vanellus miles novaehollandiae) were also found dead. These records appear to be the first to document probable secondary poisoning of shorebirds in New Zealand. There was no apparent mortality of variable oystercatchers (Haematopus unicolor). Measures are suggested to reduce shorebird mortality in future operations of this type. Monitoring of New Zealand dotterels and other shorebirds during other types of poisoning operations in coastal areas is also recommended.
The “hakawai” is a rarely-heard but dramatic nocturnal aerial display performed by Coenocorypha snipe. Although much has been written about the hakawai formerly heard on islands off Stewart Island (performed by the extinct Stewart Is snipe C. aucklandica iredalei), there are few documented reports from other populations. We describe hakawai aerial displays heard on Adams I (Auckland Is snipe C. aucklandica aucklandica), Antipodes I (Antipodes Is snipe C. aucklandica meinertzhagenae), and Campbell I (Campbell Is snipe Coenocorypha undescribed sp.) between 2001 and 2006. These include the 1st records of hakawai on Adams I and Campbell I. Based on characteristic tail feather damage believed to be caused by the display, Campbell Is snipe of both sexes performed hakawai aerial displays more frequently than has been recorded for all other Coenocorypha snipe populations. Male snipe from all 6 populations assessed exhibited a higher frequency of tail feather wear than females, and for the 3 populations with adequate data, males also had lower wing-loadings, indicative of greater flying ability. However, there was no apparent correlation between the frequency of “hakawai” feather wear and wing-loadings when comparing between populations.
The kakapo (Strigops habroptilus) is a nocturnal, herbivorous parrot that shows lek behaviour and does not breed every year. When breeding does occur, egg-laying and incubation in mid-summer are followed by a prolonged period of chick-rearing, with all parental care provided by the female. Breeding years for kakapo are associated with mast seeding years for a range of forest trees and plants, and the periodicity of kakapo breeding is linked with the periodicity of years of large seed and fruit production by their major plant foods. Kakapo are likely to have an annual cycle of gonadal growth and regression driven by the annual cycle of day length, with breeding occurring in years when kakapo respond to cues from a range of plant species that undergo masting. Kakapo breeding is initiated in response to cues that appear in early summer, but in some years there is insufficient food for the rearing of young in the following autumn. Rimu (Dacrydium cupressinum) is an important food source for chick rearing and is likely to provide an important cue for kakapo in areas where rimu is present.
Between 1992 and 2002, the 4 main colonies of the king shag (Leucocarbo carunculatus) in the outer Marlborough Sounds, New Zealand were surveyed 10 times. Additional information was gathered at 2 smaller colonies off D’Urville Island. The average total population was estimated to be 645 birds, with 92% at Duffers Reef, Trio Islands, Sentinel Rock, and White Rocks, including 102-126 breeding pairs, with an annual recruitment of 40-68 birds. Surveys before 1992 may have included only c. 40% of the population, because most counts seem to have been done during the middle of the day when significant numbers of shags were absent feeding. If historic counts at colonies are adjusted for birds absent feeding, numbers appear to have been stable for at least the past 50 years — and possibly over 100 years — which would suggest a long-term balance between recruitment and mortality.
Vegetation in the Esperance Valley, Milford catchment, Fiordland, as it was in February and March 1974, is described using quantitative data for part of the valley that included home ranges of two male kakapo (Strigops habroptilus). One home range, of only 1.8 ha, was sited at 700 – 730 m altitude and extended over a gently-sloping river terrace covered in snow totara (Podocarpus nivalis) scrub with short silver beech (Nothofagus menziesii) forest at its margins. The other home range was 4 ha in area, sited on a very steep (42°) valley wall mantled with unconsolidated avalanche debris at 800-860 m altitude, faced NW and was covered by Blechnum capense fern – shrubland and short silver beech forest communities. At that time, this valley differed from most other parts of Fiordland: although possums (Trichosurus vulpecula), stoats (Mustela erminea) and rats (Rattus spp.) were present, ungulates were absent or very localised. Results gave no indication that food was limiting kakapo numbers in the Esperance Valley and we conclude that, because of the extreme vulnerability of females and their eggs, nestlings and fledglings to introduced mammalian predators, stoats were the most probable primary cause of kakapo decline in Fiordland.
Satellite telemetry can provide unique information on the biology and behaviour of mobile animals such as albatrosses. Determining areas of concentrated activity, essential resources and time-related changes in range use is of great importance for theoretical biology, practical conservation, and fisheries management. Utilisation Distributions (UDs), from a probabilistic model of the relative time spent by an animal in an area, were prepared using a kernel function in a Geographical Information System. Properties of the model were investigated, using satellite-tracking data from six northern royal albatrosses (Diomedea sanfordi) during eight over-wintering visits to seas off South America. We analysed UD areas and shape for different settings of the kernel smoothing parameter, a variety of location subsets associated with different sample sizes, sampling time periods and telemetry regimes. Small samples and intermittent transmission regimes reduced the UD range area. Individual bird data sets were combined to give comparable UDs. The UD model may help comparison of range areas and the identification of resource use, but they cannot identify an activity without additional information. For pelagic seabirds, UD preparation and interpretation require judgement and care.
We studied the distribution along the Pacific coast of South and Central America of three large petrels species that nest on New Zealand and subantarctic islands: white-chinned petrel (Procellaria aequinoctialis), Parkinson’s petrel (P. parkinsoni) and Westland petrel (P. westlandica). During 15 cruises from 1980 to 1995, we conducted 1,020 hrs of surveys over 14,277 km2 of ocean from the shoreline to 1500 km off the coast from Chile north to Panama, and recorded 2114, 179, and 20 individuals, respectively, of the three species. White-chinned petrels occurred throughout the study area, but were most abundant off Chile, Parkinson’s petrels were most abundant along the coasts of Ecuador and Peru, and Westland petrels off southern Chile. All three species preferred waters over the continental slope, although Parkinson’s petrel was abundant also over the continental shelf during the austral winter. Densities of each species were positively related to oceanographic properties that are associated with up-welling features. Abundance estimates, analyzed using generalized additive models, peaked during the non-breeding season of each species. Estimates were 722,000 White-chinned petrels during austral autumn (95% confidence interval “CI” = 349,000 – 907,000); 38,000 Parkinson’s petrels during austral autumn (95% CI = 28,000 – 50,000); and 3,500 Westland petrels during the austral spring (95% CI = 2,000 – 6,400). Scavenging appeared to be the primary feeding method of Procellaria, a habit that would make them susceptible to mortality as a result of their regular association with commercial fishing operations, particularly the recently developed long-line fishery on the continental slope of Chile.
A census of Chatham Island shag (Leucocarbo onslowi) and Pitt Island shag (Strictocarbo featherstoni), both endemic to the Chatham Islands, New Zealand, was conducted during their 2003/04 breeding season. Totals of 271 pairs of Chatham Island shags and 547 pairs of Pitt Island shags were recorded. Compared with the only previous survey (in 1997/98), numbers of both species were significantly lower. This decline most likely reflects broad scale marine changes affecting the birds’ food supply. Alternatively, it may suggest variability in the timing of breeding between seasons.
Corrections to figures and legends in McAllan, I.A.W.; Hobcroft, D. 2005. The further spread of introduced birds in Samoa. 52(1): 16-20
Foraging of female rockhopper penguins (Eudyptes chrysocome filholi) during the chick stage was investigated at Antipodes Islands during December 2002 – January 2003. During the guard stage eight birds were tracked to foraging areas 22 – 54 km NNE or E from their nests. Birds foraging NNE did so over waters 500-1500 m deep, while those that travelled E foraged in water > 1500 m deep. The mean duration of these foraging trips was 1.37 days, significantly (p 1500 m deep. Male parents guarded the chicks more or less continuously, with most females returning to feed the chicks from mid afternoon. In the post-guard stage, most male parents returned to the nest each evening, but fewer females attended the nest at this time. Weight increases indicated that chicks were fed, on average, about once per day during both the guard and early post-guard stages. The foraging trips of female rockhopper penguins at Antipodes Islands were usually of longer duration and extended farther from the nest than birds breeding at Amsterdam, Kerguelen and Crozet Islands, but occupied a similar time and covered a greater distance than birds breeding at Staten Island. However, they were of considerably shorter duration and distance than birds breeding at Macquarie Island. This may be related to the differing marine environments around each of these breeding locations.